change svg isze code example
Example 1: svg aspect ratio
<svg viewBox="-1 -1 162 92" xmlns="http://www.w3.org/2000/svg">
<defs>
<path id="smiley" d="M50,10 A40,40,1,1,1,50,90 A40,40,1,1,1,50,10 M30,40 Q36,35,42,40 M58,40 Q64,35,70,40 M30,60 Q50,75,70,60 Q50,75,30,60" />
</defs>
<svg preserveAspectRatio="xMidYMid meet" x="0" y="0" viewBox="0 0 100 100" width="20" height="10"><use href="#smiley" /></svg>
<svg preserveAspectRatio="xMinYMid meet" x="25" y="0" viewBox="0 0 100 100" width="20" height="10"><use href="#smiley" /></svg>
<svg preserveAspectRatio="xMaxYMid meet" x="50" y="0" viewBox="0 0 100 100" width="20" height="10"><use href="#smiley" /></svg>
<svg preserveAspectRatio="xMidYMin slice" x="0" y="15" viewBox="0 0 100 100" width="20" height="10"><use href="#smiley" /></svg>
<svg preserveAspectRatio="xMidYMid slice" x="25" y="15" viewBox="0 0 100 100" width="20" height="10"><use href="#smiley" /></svg>
<svg preserveAspectRatio="xMidYMax slice" x="50" y="15" viewBox="0 0 100 100" width="20" height="10"><use href="#smiley" /></svg>
<svg preserveAspectRatio="xMidYMin meet" x="75" y="0" viewBox="0 0 100 100" width="10" height="25"><use href="#smiley" /></svg>
<svg preserveAspectRatio="xMidYMid meet" x="90" y="0" viewBox="0 0 100 100" width="10" height="25"><use href="#smiley" /></svg>
<svg preserveAspectRatio="xMidYMax meet" x="105" y="0" viewBox="0 0 100 100" width="10" height="25"><use href="#smiley" /></svg>
<svg preserveAspectRatio="xMinYMid slice" x="120" y="0" viewBox="0 0 100 100" width="10" height="25"><use href="#smiley" /></svg>
<svg preserveAspectRatio="xMidYMid slice" x="135" y="0" viewBox="0 0 100 100" width="10" height="25"><use href="#smiley" /></svg>
<svg preserveAspectRatio="xMaxYMid slice" x="150" y="0" viewBox="0 0 100 100" width="10" height="25"><use href="#smiley" /></svg>
<svg preserveAspectRatio="none" x="0" y="30" viewBox="0 0 100 100" width="160" height="60"><use href="#smiley" /></svg>
</svg>
Example 2: bootstrap 4 auto resize svg image
<img src="monkey.svg" alt="Monkey face" style="width: 100%; height: auto;">